Clock thermostat apparatus for controlling the temperature in a space at a normal control temperature during certain periods of time and reducing the controlled temperature to some lower temperature at night or during selected periods of time for both comfort and energy conservation are broadly old, as shown in the Carl G. Kronmiller U.S. Pat. No. 2,558,617, which issued June 26, 1951. In such clock thermostat apparatus, generally two levers are provided for selecting the normal control temperature and the nighttime setback temperature and when the clock thermostat time control means is present to reduce the temperature to the night setback temperature at some predetermined period of time, the homeowner can readily see that the nighttime setback temperature will be as set by the second lever. Where a temperature control apparatus has a temperature selection means and a deviation temperature selection means to preset the amount of deviation which is obtained when the time control apparatus moves into the setback time period, the operator is not as likely to notice that the setback temperature, especially when the normal temperature selection means is set rather low, will be even lower and might result in a freezing position in the home or establishment in which the clock thermostat apparatus is being used.